1. Field of the Invention
The present invention relates to a method for the continuous monitoring of the moisture content of a two-component material or product, such as margarine, and more particularly, a method which enables the continuous monitoring of the moisture content of the material through the generation of an electrical signal which is transmitted to a suitable data logging system wherein the electrical signal is converted into moisture content data and which stores the information for subsequent use. The invention further contemplates the provision of an apparatus for implementing the inventive method for continuously monitoring the moisture content of the two-component material.
During the production and processing of various products which contain a certain proportion of water or moisture, and occasionally also some salt, for instance, such as margarine, it is of considerable importance to be able to provide for the continuous monitoring of the percentage of moisture contained in the margarine which is being processed, so as to allow for the control or regulating of the amount of moisture in the margarine.
Although numerous methods and different types of apparatus are currently existent and which are specifically designed to monitor the moisture content or percentages in various materials; for example, margarine, butter, fatty substances or petroleum products, none of these are completely satisfactory in providing for the continuous and practically instantaneous monitoring of the percent moisture in a margarine processing system. Thus, some of the methods which are employed for the measurement of moisture contained in margarine utilize line cells connected to measuring systems, wherein the cells are primarily designed for use with liquid products and which, as a result, are not entirely satisfactory in providing accurate information over the moisture content in margarine, particularly when the latter is in a semi-solid to solid state when processed in a continuous flowline system. Other moisture systems which are employed for the measurement or monitoring of moisture percentages in margarine necessitate laboratory testing procedures and are much more time consuming than would a continuous monitoring arrangement, while concurrently being subject to the disadvantage of only providing intermittent testing of a material which frequently is of a non-homogeneous consistency adversely affecting read-out accuracies. Consequently, moisture readings obtained through such earlier systems, which necessitate laboratory testing are subject to being somewhat inaccurate and do not allow for the continuous control over the contents of the material, such as margarine, being processed; whereas other continuous moisture monitoring methods and apparatus are not satisfactorily applicable to the continuous moisture testing of products such as margarine.
2. Discussion of the Prior Art
Allport U.S. Pat. No. 4,395,638 discloses a method for continuously determining the water and fat content of a material, such as butter, in which the density of the substance is instantaneously measured, as well as either the dielectric constant or radioactive backscatter intensity of the material to provide a suitable electrical signal. Allport accomplishes the foregoing by connecting a radioisotope density sensor, a capacitive moisture sensor in a velocimeter to a flow conduit through which the butter is conveyed. However, the rather complex system for the non-destructive method of determining the water and fat content of the material would not provide a continuous and accurate measurement of the moisture content of a generally semi-solid to solid product, which may also be of a non-homogeneous consistency, and in which the accuracy of the sensing measurement may be further adversely influenced by voids in the material flow towards the wall surfaces of the conduit through which the material flows. Consequently, the method described in Allport for measuring the moisture content of butter would not be particularly suitable for the continuous measurement of the moisture content of margarine being processed in a continuous flowline system analogous to that contemplated by the present invention.
Keefner et al. U.S. Pat. No. 4,266,195 discloses an apparatus and method for detecting the presence of water in a non-conductive medium, such as liquid or solid grease through measurement of the electrochemical potential difference between two dissimilar metals. Although the structure of the probe disclosed in Keefner et al. is of particular use in food, petrochemical and rendering industries, and would allow for the continuous measurement of moisture content in a material, it is primarily adapted to be immersed in a liquid flowline, and its positioning and structure would preclude the use thereof in a continuous flowline system for the processing of margarine wherein the product is of a semi-solid solid consistency and is of a generally non-homogeneous consistency, unlike the product in which this probe is immersed.
Schwartz U.S. Pat. No. 4,052,667 describes a moisture meter structure wherein a metallic probe is arranged within an annular chamber, the metallic probe and a dissimilar metal being located interiorly of an insulator, and with the entire assembly being hermetically sealed with respect to the surroundings. The probe is adapted to be immersed into a liquid and is connected to a meter which functions on the principle of a solid electrolyte battery in order to provide a readout over the moisture content of a liquid in a vessel in which the probe is immersed. The probe structure or moisture meter as described by Schwartz is not adapted to facilitate the continuous monitoring of the moisture content of a product, such as margarine, being processed and which may possess a semi-solid to solid consistency, and which may also be generally non-homogeneous. Consequently, the meter for the measurement of moisture as disclosed in by Schwartz is limited to the measurement of moisture in generally homogeneous materials which have a basically liquid consistency, and would not be readily adaptable to the present invention.
Briscoe et al. U.S. Pat. No. 4,242,906 discloses a thermocouple which is encased in a non-conductive shielding and is adapted to be immersed in a liquid so as to measure thermal changes. The probe disclosed therein, which may be used in a soil hygrometer, would not appear to be applicable to a system for the continuous monitoring of moisture in a product such as margarine.
Thompson U.S. Pat, No. 4,266,188 discloses a plurality of probes which are immersible in a petroleum flowline and are adapted to provide an electrical read-out representative of the measurement of the moisture content in a two-component liquid flow stream, which may consist of water-containing crude oil. There is no disclosure nor suggestion that the moisture probe disclosed by Thompson would be applicable to a process system for margarine which may have a semi-solid to solid consistency and which may also be constituted of a non-homogeneous mixture, so as to enable the probes to provide for an accurate moisture content readout.
Numerous other moisture content monitoring systems and methods are described; for example, in U.S. Pat. Nos. 3,253,458 to Katz et al., Carlson 4,097,743, Remke et al. 3,133,437. However, none of these patents, and extensive other publications in the technology pertaining to the measurement of moisture content in a substance, are deemed to be applicable to the continuous monitoring of moisture in a two-component substance, such as margarine, which essentially consists of water and a vegetable fat.